Supremacy Clause of the US Constitution

Cite this article as: Jason Mance Gordon, "Supremacy Clause of the US Constitution," in The Business Professor, updated January 2, 2015, last accessed April 8, 2020,
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Supremacy Clause
What is the Supremacy Clause? The Constitution makes Federal law superior to state law.

Next Article: What is the Full Faith & Credit Clause?


What is the “Supremacy Clause” and “Preemption”?

Article VI, Section 2 of the US Constitution provides that the Constitution is supreme over all laws and that federal law is supreme over state law. Generally,the  state and federal governments may regulate the same type of conduct. This is known as “concurrent power”. However, any state law that prevents or interferes with the accomplishment and execution of the full purposes and objectives of Congress is invalid. Congress can expressly reserve an entire area of law for federal regulation. In such a case, the federal law “preempts” state law. If Congress does not expressly reserve the area of law for federal regulation, the state may also regulate it. State appellate courts or the US Supreme Court  may review a state law and overturn it if it determines that the law conflicts with or violates a federal law.

  • Note: Generally the state law can be more restrictive than the federal securities law.
  • Example: The Federal Government regulates the immigration process. It expressly preempts states regulating this area of law. The Federal Government also regulates the purchase and sale of securities. States are not preempted from regulating the purchase or sale of securities, but a state law may not conflict with or prohibit the accomplishment of federal law.

Discussion: Can you think of any recent state laws that were struck down because they conflicted with federal law? Can you think of any areas of law that are regulated by both state and federal law?

Discussion Input

  • An example of a State law that was struck down because it conflicts with federal law is seen in a case where a Maryland statute that required an importer to obtain a license before reselling in the original package articles imported from abroad struck down conflict with the federal power to regulate foreign commerce (Art 1, s 8 cl 3) and with the constitutional provision (Art 1 s 10, cl 12) prohibiting States from levying import duties. Asbestos is regulated by both the federal and state law. Asbestos has been known to cause conditions such as mesothelioma for many years. As a result, there has been an immense legal history involving the Asbestos materials, as well as many laws and materials that have emerged to control and limit Asbestos exposure. This is the reason why federal law and States law govern Asbestos

Practice Question: The Federal Government passes a statute that regulates certain business practices. Specifically, it requires businesses to seek federal approval through a licensing process. The law does not include a provision that specifically prohibits states from also regulating this conduct. Arizona determines that it wants to regulate this same activity by states within its borders. So, it passes a state statute that is requires businesses to also seek a state license prior to undertaking the cover practice. Is this permissible? What if the state is far more stringent that the federal statute? Less stringent? Can the state require that a state license issue before a business may apply for a federal license?

Proposed Answer

  • Federal law regulates businesses across state lines or even multiple countries. States law regulates business activities within its States like employment, insurance, and many others while federal law regulates business like the tax code, employment, and labor, antitrust law, etc. On the issue of whether the state can require that a state license be issued before a business can apply for a federal license, it is likely permissible for the state to pass such a statute that requires a business also to seek state license prior to undertaking the cover practice.  Since the law does not prohibit states law from regulating businesses, it means the state can offer business licensing to small businesses within the state and not outside its state. Business activities take place in a certain State; it is, therefore, possible for the state to require that they licensed business before the federal Government Issue their own license to businesses.

Academic Research

Ramsey, Michael D., The Supremacy Clause, Original Meaning, and Modern Law (July 6, 2013). Ohio State Law Journal, Vol. 74, p. 559 (2013). Available at SSRN:

Forero, Mateo, In the Shadow of the Supremacy Clause: How a ‘Logical-Contradiction’ Test Can Resolve the Debate Over Legislative History in FIFRA Preemption (April 1, 2016). 43 Rutgers Law Record 184, 2016. Available at SSRN:

Babich, Adam, The Supremacy Clause, Cooperative Federalism, and the Full Federal Regulatory Purpose (August 2, 2011). Administrative Law Review, Vol. 64, No. 1, 2012. Available at SSRN: or

Feldman, Stephen Matthew, Preemption and the Dormant Commerce Clause: Implications for Federal Indian Law (October 1, 1986). 64 Oregon Law Review 667 (1986). Available at SSRN:

Floyd, Graham, Federalism, Elections, Preemption, and Supremacy: The Aftermath of Inter Tribal Council (October 29, 2014). 33 MISS. C. L. REV. 235 (2014) . Available at SSRN: This article looks at Arizona v. Inter Tribal Council, a recent United States Supreme Court case dealing with the constitutionality of an Arizona voter identification law.

Squire, Richard C., Antitrust and the Supremacy Clause. Stanford Law Review, Vol. 59, No. 1, p. 77, 2006. Available at SSRN: This article addresses the issues of how the Sherman Antitrust Act applies to state economic activity and whether state law is preempted.

Hawkes, Joshua and Seidenfeld, Mark, A Positive Defense of Administrative Preemption (December 17, 2014). 22 Geo. Mason L. Rev. 63 (2014); FSU College of Law, Public Law Research Paper No. 722; FSU College of Law, Law, Business & Economics Paper No. 15-1. Available at SSRN: This article addresses the question of whether federal administrative actions do or should preempt state law.

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